Quantitative Model of Multiple Crystal Growth Rate Minima in Polymers with Regularly Spaced Substituent Groups

A simple theory has been developed to explain quantitatively the multiple crystal growth rate minima observed experimentally in polyethylene brassylates (PEBs), polymers with regularly spaced "chemical defects", in this case, diester groups separated by 11 methylenes. The minima occur at the transitions where the fold length drops from 4 to 3 repeat units and from 3 to 2 units. An analytical rate-equation model was developed with elementary attachment and detachment steps of individual monomer repeat units, also including postattachment stem lengthening (stem conversion). The model produced a good fit to experimental crystallization rate curves for PEBs of three different molecular weights. The fits confirm in a quantitative way that the anomalies are caused by the self-poisoning effect, as proposed in the original experimental report on PEBs, based on the ideas developed in previous studies on long-chain